Signal Contamination
Mechanical interaction in vibrating gyroscopes describes the unwanted transfer of energy from the driven oscillation mode to the detection mode. This drive sense mode coupling is measured in degrees of phase or in quadrature output and governs the baseline zero-rate offset of the sensor. The effect ceases to apply when the sensor is at rest and does not experience any drive force.
Mechanical Transmission
Manufacturing imperfections introduce asymmetries in the silicon suspension. This drive sense mode coupling often stems from tiny variations in the sidewall angles of the etching process. Consequently, the primary oscillation path is no longer orthogonal to the sensing axis.
Force transfer occurs even in the absence of an external angular rate, which creates an erroneous signal.
Calibration Overhead
Compensating for this cross-axis error requires electronic quadrature cancellation. The drive sense mode coupling is evaluated during final factory testing, and correction coefficients are stored in the memory of the integrated circuit. This calibration phase adds to the assembly time but ensures the sensor meets performance targets under temperature variations.
Symmetric Design
Suspension architecture represents the main defense against cross-axis energy transfer. High-symmetry designs with balanced anchors reduce the susceptibility to drive sense mode coupling. These structures must be verified using finite element analysis before committing to a manufacturing run.
